Answer:
D. by taking in oxygen and cleaning out waste gases like carbon dioxide.
Explanation:
The respiratory system cleans out your carbon dioxide and replaces it with oxygen.
The answer is whales. In the Antartic and Arctic regions, krills and whales are very abundant in numbers. Whales are number one consumer of krills in these regions. They can feed on a large swarm of krills when they feed. They also have less competition on these icy waters. They gain energy every time from eating them.
